The efficacy of low-level 940 nm laser therapy with different energy intensities on bone healing

Abstract

The aim of this study was to evaluate the efficacy of low-level 940 nm laser therapy with energy intensities of 5, 10 and 20 J/cm 2 on bone healing in an animal model. A total of 48 female adult Wistar rats underwent surgery to create bone defects in the right tibias. Low-level laser therapy (LLLT) was applied immediately after surgery and on post-operative days 2, 4, 6, 8, 10 and 12 in three study groups with energy intensities of 5 J/cm 2 , 10 J/cm 2 and 20 J/cm 2 using a 940 nm Gallium-Aluminium-Arsenide (Ga-Al-As) laser, while one control group underwent only the tibia defect surgery. All animals were sacrificed 4 or 8 weeks post-surgery. Fibroblasts, osteoblasts, osteocytes, osteoclasts and newly formed vessels were evaluated by a histological examination. No significant change was observed in the number of osteocytes, osteoblasts, osteoclasts and newly formed vessels at either time period across all laser groups. Although LLLT with the 10 J/cm 2 energy density increased fibroblast activity at the 4th week in comparison with the 5 and 20 J/cm 2 groups, no significant change was observed between the laser groups and the control group. These results indicate that low-level 940 nm laser with different energy intensities may not have marked effects on the bone healing process in both phases of bone formation.

Comparative Evaluation of Effect of Irradiation Using Low- Level Laser Therapy With Two Different Wavelengths on Stability of Dental Implants

“…This is in line with studies done by Mayer et al [15] , Stein et al 2005 [23] , Deise A.A. Pires Oliveira et al [24] 2008 and Keiko Fujimoto et al 2010 [22] in which that LLLT stimulated bone nodule formation via the acceleration of cellular proliferation and differentiation, which was accompanied by increased alkaline phosphatase (ALP) activity and osteocalcin expression, suggesting direct stimulatory effects on bone formation by laser irradiation. This study did not show any difference in the implant stability between both the groups, which may be due to better oral hygiene maintenance of the patient and no significant crestal bone loss, which were in accordance with studies done by Kerem Turgut Atosoy et al [26] 2017, Paulo Sergio Bossini, Ana Claudia Muniz Renno et al [25] 2011 in which similar response of osteoblasts to different wavelengths and dosages of low-level laser therapy was seen.…”

Efeitos da fotobiomodulação (laser de baixa intensidade) na cicatrização de feridas: revisão integrativa

“…Observou-se nessa revisão uma diferença na densidade de energia utilizada, bem como na frequência de utilização e na potência. Densidades de energia variaram de 1 a 20 J/cm 2 , sendo a mais utilizada a de 4J/cm 2 (Barbosa et al, 2020;Feitosa et al, 2015;Cunha et al, 2019;Taradaj et al 2018), 5J/cm 2 (Atasoy et al, 2017;Sousa et al, 2015;Cunha et al, 2019) (Nilforoushzadeh et al, 2019;Fioruzi et al, 2018;, 2J/cm 2 (Martins et al, 2015), 3J/cm 2 (Scherer et al 2019;De Souza et al, 2018), 0,25 J/cm 2 (Barbosa et al, 2020), 10 J/cm 2 e 20 J/cm 2 (Atasoy et al, 2017) e 8J/cm 2 ( Sousa et al, 2015). Observou-se, quanto aos parâmetros de aplicação da FBM, que eles variaram de 632,8 a 940 nm, mas a maior parte dos estudos (12= 75%) utilizou entre 632,8 a 670 nm, demonstrando uma padronização na utilização nas feridas.…”

“…Outro ponto importante que merece destaque foi a potência utilizada que variou 1,08 mW a 6W, porém, a potência de 30 mW foi a prevalente em seis artigos (37,5%). Cabe ressaltar que alguns autores utilizaram grupos com diferentes densidades de energia, comprimento de ondas e potência (Barbosa et al, 2020;Atasoy et al, 2017;Sousa et al, 2015;De Sousa et al, 2018;Nilforoushzadeh et al, 2019;Cunha et al, 2019;Taradaj et al, 2018;Kasemikhoo et al, 2018).…”

Effect of S53P4 bioactive glass and low-level laser therapy on calvarial bone repair in rats submitted to zoledronic acid therapy

“…When used in bone repair process, the PBMT provides bio-stimulation, accelerating osteocyte metabolism and stimulating mesenchymal cells to differentiate into osteoblasts, increased ATP and alkaline phosphatase (ALP) concentration and the release of calcium, and promotes a specific stimulus to osteogenesis during the initial stages of healing. With this, there is an increase in the release of hydroxyapatite crystals that will favor maturation of newly formed bone tissue, being also helpful in treating osteonecrosis lesions 33,34 . However, there is no consensus on the laser application protocol to be used, as showed in Table 1 [35][36][37][38] .…”